GB2488845A

GB2488845A - An LED lamp unit

Info

Publication number: GB2488845A
Application number: GB1112034.2A
Authority: GB
Inventors: Andrew Johnson
Original assignee: Aurora Ltd
Current assignee: Aurora Ltd
Priority date: 2011-07-13
Filing date: 2011-07-13
Publication date: 2012-09-12
Anticipated expiration: 2031-07-13
Also published as: ZA201400096B; AU2012282258A1; CN103958961A; EP2732200A1; WO2013008030A1; GB201112034D0; GB2488845B

Abstract

An LED lamp unit 100 engages with, and receives electrical power from, a lamp unit holder. The LED lamp unit 100 has LEDs, a rechargeable power source 106, a first electrical connecting means 112 to connect the LED lamp unit 100 to a first electrical power source 118 in the lamp holder and a second electrical connecting means 110 connects the LED lamp unit 100 to a second electrical power 120 source to charge the rechargeable power source 106.

Description

I

An LED lamp unit

Field of the Invention

The present invention relates to LED lamp units. It is particularly applicable, but in no way limited, to LED lamp units which are capable of providing both normal and emergency lighting.

Background to the Invention

LED (light emitting diodes) lamp units, including LED tubes which can replace conventional fluorescent lamps, are becoming increasingly widely used. LED tube lamps have advantages over conventional lamps because of the properties of LEDs.

These properties include low power consumption, long lifespan, rapid start-up and directional ability. As a result, new commercial and industrial buildings are usually fitted out with LED lamps, including LED tube lamps and existing commercial and industrial buildings are being retro-fitted with these types of lamp over time.

Emergency lights to aid escape from a building in an emergency must be provided in commercial and industrial buildings, as well as in other locations, and special emergency LED lights have been designed for that purpose. These emergency lights are generally of two main types. So-called "non-maintained" emergency lights illuminate only when the normal mains electricity supply fails. So-called "maintained" emergency lights function as a conventional light when the normal mains electrical supply is on, and also function as an emergency light when the normal mains electricity supply fails.

One type of emergency LED light is described in US2OI 1/0084554 (Feng Tian et al).

This document describes an LED tube lamp which includes a rechargeable battery.

The battery, which is charged when the unit is connected to a live AC power source, provides power to a second set of LEDs in the event that the mains AC power supply is interrupted.

This arrangement suffers from a number of disadvantages. One inherent disadvantage is that the battery only charges when the unit is switched on and AC mains electricity is flowing. If the lamp unit is located in an area that is occupied infrequently, and therefore the lights are switched on infrequently, or is in an area that has the benefit of good natural light and the lights are therefore rarely required, then the battery will not be charged. This would result in the emergency light failing to function in the event of an AC mains supply failure.

It is an object of the present invention to overcome or at least mitigate some or all of these disadvantages. It is a further object of the invention to provide an LED tube lamp unit that can be installed as a replacement for a conventional fluorescent tube lamp or a conventional LED tube lamp, in any suitable lamp holder, and provide the additional functionality of a maintained emergency light. That is to say, a light fitting which was never designed as an emergency light can be converted into an emergency light by way of the present invention.

Summary of the Invention

According to the first aspect of the present invention there is provided an LED lamp unit adapted to engage with, and receive electrical power from, an LED lamp unit holder, said LED lamp unit comprising:-one or more LEDs; a rechargeable power source; a first electrical connecting means adapted to connect the LED lamp unit to a first electrical power source in the lamp holder; a second electrical connecting means adapted to connect the LED lamp unit to a second electrical power source adapted to charge the rechargeable power source.

By providing an electrical connection means in the LED lamp unit to enable a second power supply to be connected to the LED lamp unit it is possible to ensure that the rechargeable power supply is kept charged, regardless of whether the lamp unit is on or off.

Preferably the first electrical power source comprises a switched power source.

This corresponds to the conventional switched power source used to turn the LED lamp unit on and off in normal operation.

Preferably the second electrical power source comprises a permanent, unswitched power source. Permanent electrical supplies are provided in commercial and industrial premises. By providing a second electrical connecting means as part of the LED lamp unit itself, rather than as part of the lamp unit holder, it is possible to connect the lamp unit to such a supply, without the requirement for a special, maintained emergency lamp holder which includes a secure supply.

Preferably the first electrical power source comprises an alternating current power source, and preferably the second electrical power source comprises an alternating current power source.

Preferably the LED lamp unit further includes a housing. This housing houses the LED array(s), the LED drivers and associated circuitry, the rechargeable power source and associated charging circuitry, and any heat sinks. Typically the first and second electrical connecting means extend from the housing.

Preferably the housing comprises a hollow tubular body wherein at least part of the tubular body is light penetrable. Since LEDs are directional, only that part of the tubular body facing into the space to be illuminated needs to be light penetrable.

Preferably the unit further comprises a photoelectric component.

Preferably the photoelectric component functions as a switch between the first electrical power source and the LEDs.

Preferably the photoelectric component acts as a switch between the rechargeable power source and the LEDs.

In a further preferred embodiment the photoelectric component may be replaced by or augmented with a passive infrared sensor (PIR sensor) or a microwave sensor.

Both these types of sensor are capable of detecting the presence of a human or animal body in the space covered by the sensor.

In a particularly preferred embodiment the second electrical connecting means comprises an electrical cable, attached at one end to circuitry in the housing and optionally with an electrical connector on the end of the cable remote from the LED lamp unit. This cable can be used to connect the LED lamp unit either directly or indirectly to a secure power supply.

Preferably the electrical cable passes through the body of the housing.

Advantageously the cable can pass through that part of the housing which is not light penetrable, and thus exits the housing on the side of the lamp unit away from normal view.

Preferably the LED lamp unit further comprises circuitry adapted to cause the LED array to operate at less than normal operating brightness when power is provided by the rechargeable power source. Because the light output requirements for normal lighting and emergency lighting are different, the emergency lighting requirement being for less light than normal lighting, this arrangement enables the rechargeable power source to last longer than if it was required to power all of the LEDs.

Preferably the unit comprises a plurality of LEDs in an array.

In an alternative embodiment the LED lamp unit further comprises circuitry adapted to cause only part of the LED array to operate when power is provided by the rechargeable power source.

The present invention therefore encompasses an LED lamp unit having a rechargeable power source and connections to two external power sources. One of the external power sources is the usual switched supply, and the other is a permanent supply. This means that no special lamp holder is required to create a maintained emergency light and that a secure power supply can be supplied to charge the rechargeable energy source, even when the LED lamp unit is switched off.

Brief description of the drawings

The present invention will now be described by way of example only with reference to the following drawings in which:-Figures 1 and 2 illustrate typical wiring diagrams for LED lamp units according to the present invention for luminaires with electronic ballasts or with magnetic ballasts respectively; Figure 3 illustrates a perspective view of an LED lamp unit according to the present invention; Figure 4 illustrates by way of an exploded diagram how the components of an LED lamp unit according to the present invention are accommodated within a tubular housing.

Description of the preferred embodiments

The present invention will now be described by way of example only. These are not the only ways in which the invention may be put into practice but they are the best ways currently known to the applicant.

Referring to Figure 1, this shows in diagrammatic format an LED lamp unit 100 having a tubular shape and adapted to engage with an LED lamp unit holder having fittings 116 at each end of the lamp holder. The LED lamp unit 100 has at both ends of the tube a pair of pins 112, 114, being in combination a first electrical connecting means, and these pins engage with fittings 116 of the LED lamp unit holder both to retain the LED lamp unit 100 in place in the lamp holder, and to form an electrical connection with the lamp holder. The LED lamp holder is supplied from a first electrical power source 118, typically alternating current (AC) mains power.

Is it envisaged that the LED lamp unit will run off alternating current, but it is equally possible to use direct current if that is required.

The LED lamp unit 100 includes an LED driver 104, which is electrically connected to the pair of pins 112 in order to receive electrical power from the lamp unit holder, and to one or more LEDs 102. When the LED lamp unit 100 is engaged with the LED lamp holder, and the first electrical power source 118 is on, current supplied to LED driver 104 via the pair of pins 112 and the fittings 116 is typically converted into direct current (DC), which is supplied to one or more LEDs 102. As a result, LEDs 102 emits light for providing illumination.

The arrangement described thus far is that of a conventional LED tubular lamp unit known per se. However, the lamp unit 100 also includes a charging circuit 108 and a rechargeable power source in the form of a battery 106. The charging circuit is electrically connected by way of a second electrical connecting means to a second power source 120 by way of terminals 110. The charging circuit 108 is also connected to the rechargeable power source 106 and to one or more LEDs 102.

Stored electrical power from the rechargeable power source 106 can be supplied to one or more LEDs 102 via charging circuit 108 in the event of a power failure. The rechargeable power source 106 can be a battery, or some other device such as a capacitor or a fuel cell.

Using this new type of LED lamp unit any conventional lamp holder may be converted into a maintained emergency light fitting. When the LED lamp unit 100 is fitted into the lamp holder the LED lamp unit is connected via the pins 112 to a first electrical power source provided by the lamp holder. In addition, terminals 110 are electrically connected to second electrical power source 120, which is typically a permanent, or always on", electrical power source. This second electrical power source 120 is utilised by the charging circuit to charge, or maintain the charge of, the rechargeable power source 106. The rechargeable power source 106 is thus maintained in a charged state, regardless of whether the first electrical power source 118 is on or off.

When first electrical power source 118 is on, one or more LEDs 102 emit light for providing illumination in a conventional manner as described above. When first electrical power source 118 is off, current is no longer supplied to one or more LEDs 102 via LED driver 104.

The charging circuit 108 is adapted to detect the status of the power supply to the second electrical connecting means 110. Thus, in normal use, when power is supplied to the connecting means 110, the first electrical power source 118 causes one or more LEDs 102 to operate normally as required and no power is supplied to the LED5 by the rechargeable power source 106. However, when there is a power failure and both the first electrical power source 118 and the second electrical power source 120 are off, power from the rechargeable power source 106 is supplied to one or more LEDs 102 in order to provide emergency light. The various electrical power supply arrangements described above are summarised in Table 1.

Table I

Status of the first electrical Status of the second electrical Status of one or power source 118 power source 120 more LEDs 102

ON ON ON

OFF ON OFF

OFF OFF ON

In a preferred embodiment, circuitry is provided such that when the lamp unit is functioning as an emergency light the LED array is illuminated at less than normal operating brightness. This conserves the operational life of the rechargeable power source in an emergency power situation.

Optionally, the charging circuit 108 may supply a lower current from the rechargeable power source 106 to one or more LEDs 102 than is supplied by the LED driver 104 in normal operation, leading to a lower level of illumination and thus conserving the rechargeable power source 106.

In a further preferred embodiment, circuitry is provided such that when the lamp unit is functioning as an emergency light only part of the LED array is illuminated. This also conserves the rechargeable power source.

Optionally the LED array may be divided in to two or more LED arrays. The division of LED arrays into sub arrays is known, and this technology finds useful application in this invention.

In a further preferred embodiment a photoelectric component is provided (not shown) which can act as a switch to turn off the LED array in the event that there is sufficient light in the vicinity of the lamp unit such that artificial illumination is not required. This light operated switch can operate on the LED array when the unit is in normal operation, or when the unit is operating as an emergency light, or both.

Again, photoelectric cells and the associated circuitry to create a light operated switch are well known and can usefully be employed in the present invention.

In addition to or instead of a photoelectric component, a passive infrared sensor (PIR sensor) or a microwave sensor can be incorporated into the LED lamp unit.

Both of these types of sensor are known and are capable of detecting the presence of a human or animal body in the space covered by the sensor. These sensors are therefore capable of turning the light or lights off when the area is unoccupied and turning it on when the area is occupied. These sensors are known, as is the associated circuitry to create a motion or body activated switch, and can usefuliy be employed in the present invention.

Figure 2 illustrates a similar lamp unit to that illustrated in Figure 1 and an equivalent numbering system to that in Figure 1 has been used. In the arrangement shown in Figure 2 the lamp holder includes a magnetic ballast and if the lamp holder was designed to accept fluorescent tubes then it is necessary to replace the fluorescent starter with an LED starter/fuse unit. Otherwise the components and operation of the arrangement shown in Figure 2 are the same as for those shown in Figure 1.

Figure 3 illustrates the typical appearance of an LED lamp unit 300 according to the present invention. This takes the form of a tube 301, the front part of which is transparent or translucent to visible light. The back part of the tube 303 is not necessarily transparent to visible light and is preferably not transparent as it can be used to hide the electronic circuitry required to make the lamp unit function, and that is shown in more detail in Figure 4.

Connector pins 312 and 314 in end caps located at each opposite end of the tube serve to engage with, and form electrical connection with, a lamp holder which may be of a conventional type.

A second electrical connecting means, in the form of a two core electrical cable 311, extends from the rear or back part of the tube 303, being the part of the tube which is generally not light transparent. Thus, when the LED lamp unit 300 is installed in a lamp holder, and the electrical connecting means 311 is fed off and connected to a secure power supply, then the connecting means 311 remains substantially invisible to anyone standing in the room and when viewed from beneath the lamp unit.

It is preferred to use a two core cable but it is equally possible to use two separate cables.

Also shown in Figure 3 is an on/off switch 400, shown in more detail as item 18 in Figure 4. This switch can be used to disconnect the rechargeable battery from the circuit. This facility would be used, for example, when the unit is in transit. It is anticipated that the unit will be manufactured and tested with a charged, or partially charged battery. However, without this switch, when the unit is disconnected from the test mains supply and packed into its box for transit, the LED lighting array 102 would automatically come on and the battery will become fully discharged in a matter of hours. This is undesirable and can be prevented by switching the switch 400/18 to the OFF" position, while the battery is still in a charged or partially charged state.

In that condition the LEDs are no longer powered by the battery and the LED array will no longer come on when the unit is disconnected from the mains electricity supply. The unit will therefore arrive at its destination with the rechargeable battery still in a charged or partially charged state. On installation the installer simply moves the switch to the "ON" position and the unit functions normally as an emergency light.

The switch can be located in any suitable location. It is preferred that the switch is located away from the transparent/translucent part of the fitting through which light is emitted. That is to say, it is preferred if the switch 18 is located on the non-transparent part or rear of the LED lamp unit, which is not visible when the lamp unit is in its installed position in an LED lamp unit holder. It is also preferred that the switch is located in a position such that it does not interfere with any part of the lamp holder or with any starter/fuse or other items that project from the LED lamp unit holder, as shown by item 18 in Figure 4.

Figure 4 illustrates in exploded view format the components used in the construction of an LED lamp unit according to the present invention. A key to the components in Figure 4 is shown in Table 2 below.

Table 2

I Diffuser 2 LED module 3 Screw 4 Washer Lamp holder 6 Screw 7 End car 8 Cable 9 LED driver MYLAR Plastic sleeve for LED driver 11 Cable 12 Battery 13 Insulation sheet 14 Copper Battery charger PCD 16 Aluminium tube section 17 Cord grip 18 Battery disconnect switch 411 Two core lead for connection to secure supply 500 LED charge indicator An indicator means which provides a visual indication of the state of the LED lamp unit, and in particular its ability to function as an emergency light, is provided by one or more coloured LEDs 500, shown in Figure 4. In this case a single green LED is incorporated into the LED array 102. This green LED is a charge indicator and illuminates when the battery charging circuit is functioning. It follows therefore that a simple visual inspection of such units, looking for the green lights, provides a simple visual check that everything is in order.

It will also be appreciated that other colours of LED(s) could be provided to perform the same function of providing a visual indication that the charging circuit is functioning correctly. lt is also not necessary that this indication function is performed by an LED, but an LED is the preferred form of visual indicator means.

Claims

Claims 1. An LED lamp unit adapted to engage with, and receive electrical power from, an LED lamp unit holder, said LED lamp unit comprising:-one or more LEDs; a rechargeable power source; a first eiectrical connecting means adapted to connect the LED Jamp unit to a first electrical power source in the lamp holder; a second electrical connecting means adapted to connect the LED lamp unit to a second electrical power source adapted to charge the rechargeable power source.
2. An LED lamp unit according to claim 1, in which the first electrical power source comprises a switched power source.
3. An LED lamp unit according to claim I or claim 2, in which the second electrical power source comprises a permanent, unswitched power source.
4. An LED lamp unit according to any preceding claim, in which the first electrical power source comprises an alternating current power source.
5. An LED lamp unit according to any preceding claim, in which the second electrical power source comprises an alternating current power source.
6. An LED lamp unit according to any preceding claim wherein the LED lamp unit further includes a housing.
7. An LED lamp unit according to Claim 6 wherein the housing comprises a hollow tubular body wherein at least part of the tubular body is light penetrable.
8. An LED lamp unit according to any preceding claim wherein the unit further comprises a photoelectric component.
9. An LED lamp unit according to Claim 8 wherein the photoelectric component functions as a switch between the first electrical power source and the LEDs.
10. An LED lamp unit according to Claim 8 and Claim 9 wherein the photoelectric component acts as a switch between the rechargeable power source and the LEDs.
II. An LED lamp unit according to any preceding Claim wherein the second eiectrical connecting means comprises an electrical cable, optionally with an electrical connector on the end of the cable remote from the LED lamp unit.
12. An LED lamp unit according to Claim 11 when dependent on Claim 6 or Claim 7 wherein the electrical cable passes through the body of the housing.
13. An LED lamp unit further comprises circuitry adapted to cause the LED array to operate at less than normal operating brightness when power is provided by the rechargeable power source.
14. An LED lamp unit according to any preceding claim wherein the unit comprises a plurality of LEDs in an array.
15. An LED lamp unit according to Claim 14 further comprising circuitry adapted to cause substantially the whole LED array to operate when the lamp unit is connected to the first electrical power source and only part of the LED array to operate when power is provided by the rechargeable power source.
16. An LED lamp unit substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS Catms1. An LED lamp unit adapted to: engage with, and receive electrical power from, an LED lamp unit holder, said LED lamp unit comprising:-one or more LEDs; a rechargeable power source; a first electrical connecting means adapted to connect the LED lamp unit toe first: electrical power source in the lamp holder; a second electrical connecting means adapted to connect the LED lamp unit to a second electrical poier source adapted to charge the rechargeable power source.2. An LED tamp' unit according to claim 1, in which the first electrical power source comprises a switched power source.3 An LED lamp unit according to claim I or claim 2, tn which the second electrical power source comprises a' permanent, unswitched power source.o 4. An LED lamp unit according to any preceding claim, in which the first electrical power source comprises an alternating current power source.1⁄4 5. An LED lamp unit according to any preceding claim, in which the second electrical power source comprises an alternating current power source.6. An LED lamp unit according to any preceding claim, wherein the LED lamp unit further includes a housing.7. An LED lamp unit according to Claim 6 wherein, the housing comprises a hollow tubular body wherein at least part of the. tubular body is light penetrable..8. An LED lamp unit according to any preceding claim wherein the unit further comprises a photoelectric cc.m'ponent.9. An LED lamp unit according to Claim S wherein the photoelectric component functions as a switch between the first electrical power source and the LEDa iO An LED lamp unit according to claim 8 and Claim S wherein the photoelectric component acts as. a switch between the rechargeable power source and the: LEDs.11. An LED lamp unit according to any preceding Claim wherein the second electrical connecting means comprises an electrlcal cable, optioriaHy with sri electrical connector on the end: of the cable remote from, the LED lamp unit, 12. An LED lamp unit, according to Claim ii when dependent on Claim 6 or Claim 7 wherein the electrical cable passes through the body of the housing..13-An LEO lamp unit according to an.y preceding Claim further comprising circuitry adapted to cause the LED array to operate at less than normal operating brightness when power is provided by the rechargeable power source. r14. An LED lamp unit according to any preceding claim wherein the unit o comprises a plurality of LEDs in an array 2.0 15.: An LED lamp unit according to Claim 14 further compHsing circuitry adapted to": cause substantially the whole LED array to operate when the lamp unit is connected to the first electrical power source and only part of the LE.D array to operate: when power is provided by the rechargeable power source.16. An. LED' lamp unit substantially as herein descrIbed with reference to and as illustrated in any cornbihation of the' accompanying drawings.